Isopropyl levulinate

All the spectroscopic approaches applied for structural characterization of mixtures derive from methods originally developed for screening libraries for their biological activities. They include diffusion-ordered spectroscopy [15-18], relaxation-edited spectroscopy [19], isotope-filtered affinity NMR [20] and SAR-by-NMR [21]. These applications will be discussed in the last part of this chapter. As usually most of the components show very similar molecular weight, their spectroscopic parameters, such as relaxation rates or selfdiffusion coefficients, are not very different and application of these methodologies for chemical characterization is not straightforward. An exception is diffusion-edited spectroscopy, which can be a feasible way to analyze the structure of compounds within a mixture without the need of prior separation. This was the case for the analysis of a mixture of five esters (propyl acetate, butyl acetate, ethyl butyrate, isopropyl butyrate and butyl levulinate) [18]. By the combined use of diffusion-edited NMR and 2-D NMR methods such as Total Correlation Spectroscopy (TOCSY), it was possible to elucidate the structure of the components of this mixture. This strategy was called diffusion encoded spectroscopy DECODES. Another example of combination between diffusion-edited spectroscopy and traditional 2-D NMR experiment is the DOSY-NOESY experiment [22]. The use of these experiments have proven to be useful in the identification of compounds from small split and mix synthetic pools. 

Figure 24 (a) ID 400 MHz H NMR spectrum of the nine-component mixture in CDC13. (1) DL-isocitric lactone, (2) (S)-(+)-0-acetylmandelic acid, (3) DL-iV-acetylho-mocysteine thiolactone, (4) ( + )-sec-butyl acetate, (5) propyl acetate (6) isopropyl butyrate, (7) ethyl butyryl acetate, (8) butyl levulinate, (9) hydroquinine-9-phenanthryl ether, (b) PFG ID H NMR spectrum of the mixture without hydroquinine-9-phe-nanthryl ether, (c) PFG ID H NMR spectrum of the nine component mixture using LED sequence. Chemical shifts arising from compounds 1 and 2 are shown. All other shifts are from compound 9. The PFG conditions were the same as in (b). 

Dense needles from isopropyl ether or methanol, mp 119-121. [a]jf +61 (c 1 in chloroform), Soly (mg/ml) sesame oil 25-29 levulinic acid butyl ester 350-400. therap CAT Progestogen. 

Acetyl propane. See Methyl isopropyl ketone Acetyl 2-propanone. See Acetylacetone Acetylpropionic acid 3-Acetylpropionic acid p-Acetylpropionic acid. See Levulinic acid Acetylpropionyl. See Pentane-2,3-dione Acetyl pyrazine. See 2-Acetyl pyrazine 2-Acetyl py razi ne... 

Isopropyl hexanoate Isopropyl isobutyrate Isopropyl isovalerate Isopropyl myristate p-Isopropylphenylacetaldehyde Isopropyl phenylacetate 3-(p-lsopropylphenyl) propionaldehyde Isopropyl propionate Isopropyl tiglate Isopulegol Isopulegone Isopulegyl acetate Isoquinoline Isosafrole Isovaleraldehyde Isovaleric acid cis-Jasmone Laurie aldehyde Lauryl acetate Lauryl alcohol Lepidine Levulinic acid d-Limonene dl-Limonene l-Limonene... 

Isobutyl isocyanate Isopropylamine Isopropyl bromide Isopropyl isocyanate Laurie acid Levulinic acid Malonic acid 2-Mercaptoethanol Meroxapol 105 Meroxapol 172... 

Acetic acid Acetone L-Camphor Caprolactam 2,2-Dimethylpropanol Ethylcellulose Ethylene 2-(5-Ethyl-2-pyridyl)ethyl acrylate Heptyl alcohol N-Isopropyl-N -phenyl-p-phenylenediamine Levulinic acid Nonanoic acid Rosin plastic mfg., cellulose propionate Propionic acid plastic pipe Polypropylene plastic resins Cobalt phosphate (ous) plastic wood s-Amyl acetate... 

Isobutyric acid Isopropyl benzoate Lauralkonium chloride Levulinic acid Magnesium borate... 

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